Recent years have seen an increasing number of diabetic patients and patients suffering from the complications thereof, and an increasing incidence of diabetes in young people resulting from improvements in the standard of living, changes toward European and American styles of eating, a growing tendency toward insufficient exercise, and the like.
Generally, diabetes mellitus includes insulin-dependent (type I) and non-insulin-dependent (type II) diabetes, and 90% or more of all diabetic patients suffer from the latter.
For treating diabetes, in addition to therapeutic exercise and dietary management, insulin injections are used for type I diabetes and oral drugs other than insulin are mainly used for type II diabetes. Oral drugs known to be useful for treating type II diabetes include insulin secretion stimulators such as sulfonyl ureas (SUs), and anaerobic glycolysis promoters such as biguinides.
The primary goal of treating diabetes is to prevent the development of diabetic complications. However, according to clinical reports concerning the prognoses of patients administered with an insulin secretion stimulator and an anaerobic glycolysis promoter over a long period of time, it is clear that the effect of preventing the development of diabetic complications is not always satisfactory.
Further, it is reported that the administration of various insulin secretion stimulators may cause severe, prolonged hypoglycemia, and, particularly, the long-term administration thereof may pose an increased burden on the pancreas, causing a transition of the pathological state to type I diabetes. It is also reported that the administration of an insulin secretion stimulator may cause chronic hypersecretion of insulin, and that this chronic hypersecretion of insulin, as a result, leads to the development of complications.
As for the anaerobic glycolysis promoters, serious side effects, such as severe lactic acidosis, hypoglycemia and the like have been reported (see, e.g., Rinsho Seijinbyo (The Journal of Adult Diseases), 6(6), 859–865 (1976)).